selftests/bpf: Add kprobe session cookie test

Adding kprobe session test that verifies the cookie value
get properly propagated from entry to return program.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240430112830.1184228-8-jolsa@kernel.org

diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h
index cb946d9fd63a13c269d77b1227e5d2f791727c0d..be91a6919315888de35665d71affcdcc54d52aed 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_kfuncs.h
+++ b/tools/testing/selftests/bpf/bpf_kfuncs.h
@@ -77,4 +77,5 @@ extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
                                      struct bpf_key *trusted_keyring) __ksym;
 
 extern bool bpf_session_is_return(void) __ksym __weak;
+extern long *bpf_session_cookie(void) __ksym __weak;
 #endif

diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
index 42d6592f1e7fcbd43382c04810051709846b56e0..960c9323d1e0f594f665640b30369d2f69dbb256 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -5,6 +5,7 @@
 #include "kprobe_multi_empty.skel.h"
 #include "kprobe_multi_override.skel.h"
 #include "kprobe_multi_session.skel.h"
+#include "kprobe_multi_session_cookie.skel.h"
 #include "bpf/libbpf_internal.h"
 #include "bpf/hashmap.h"
 
@@ -363,6 +364,38 @@ cleanup:
        kprobe_multi_session__destroy(skel);
 }
 
+static void test_session_cookie_skel_api(void)
+{
+       struct kprobe_multi_session_cookie *skel = NULL;
+       LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+       LIBBPF_OPTS(bpf_test_run_opts, topts);
+       struct bpf_link *link = NULL;
+       int err, prog_fd;
+
+       skel = kprobe_multi_session_cookie__open_and_load();
+       if (!ASSERT_OK_PTR(skel, "fentry_raw_skel_load"))
+               return;
+
+       skel->bss->pid = getpid();
+
+       err = kprobe_multi_session_cookie__attach(skel);
+       if (!ASSERT_OK(err, " kprobe_multi_wrapper__attach"))
+               goto cleanup;
+
+       prog_fd = bpf_program__fd(skel->progs.trigger);
+       err = bpf_prog_test_run_opts(prog_fd, &topts);
+       ASSERT_OK(err, "test_run");
+       ASSERT_EQ(topts.retval, 0, "test_run");
+
+       ASSERT_EQ(skel->bss->test_kprobe_1_result, 1, "test_kprobe_1_result");
+       ASSERT_EQ(skel->bss->test_kprobe_2_result, 2, "test_kprobe_2_result");
+       ASSERT_EQ(skel->bss->test_kprobe_3_result, 3, "test_kprobe_3_result");
+
+cleanup:
+       bpf_link__destroy(link);
+       kprobe_multi_session_cookie__destroy(skel);
+}
+
 static size_t symbol_hash(long key, void *ctx __maybe_unused)
 {
        return str_hash((const char *) key);
@@ -729,4 +762,6 @@ void test_kprobe_multi_test(void)
                test_attach_override();
        if (test__start_subtest("session"))
                test_session_skel_api();
+       if (test__start_subtest("session_cookie"))
+               test_session_cookie_skel_api();
 }

diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c b/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c
new file mode 100644 (file)
index 0000000..d490708
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <stdbool.h>
+#include "bpf_kfuncs.h"
+
+char _license[] SEC("license") = "GPL";
+
+int pid = 0;
+
+__u64 test_kprobe_1_result = 0;
+__u64 test_kprobe_2_result = 0;
+__u64 test_kprobe_3_result = 0;
+
+/*
+ * No tests in here, just to trigger 'bpf_fentry_test*'
+ * through tracing test_run
+ */
+SEC("fentry/bpf_modify_return_test")
+int BPF_PROG(trigger)
+{
+       return 0;
+}
+
+static int check_cookie(__u64 val, __u64 *result)
+{
+       long *cookie;
+
+       if (bpf_get_current_pid_tgid() >> 32 != pid)
+               return 1;
+
+       cookie = bpf_session_cookie();
+
+       if (bpf_session_is_return())
+               *result = *cookie == val ? val : 0;
+       else
+               *cookie = val;
+       return 0;
+}
+
+SEC("kprobe.session/bpf_fentry_test1")
+int test_kprobe_1(struct pt_regs *ctx)
+{
+       return check_cookie(1, &test_kprobe_1_result);
+}
+
+SEC("kprobe.session/bpf_fentry_test1")
+int test_kprobe_2(struct pt_regs *ctx)
+{
+       return check_cookie(2, &test_kprobe_2_result);
+}
+
+SEC("kprobe.session/bpf_fentry_test1")
+int test_kprobe_3(struct pt_regs *ctx)
+{
+       return check_cookie(3, &test_kprobe_3_result);
+}